DESCRIPTION

This routine outputs a matrix in column order to a file specified by
its file name. All row entries of a given column are output before
advancing to the next column.
"file_name" is a pointer to a character array containing the name
of the file to write the matrix contents to. If "file_name" is NULL
or equal to '\0', output is directed to STDOUT. Otherwise, the file
is created or the existing copy is overwritten.
"mp" is a pointer to the Matrix whose contents are to be written. If the
matrix is NULL, then this routine is a NOP.
The output format depends on the magnitude of the maximum absolute value in
the matrix. If the maximum is < 0.01 or greater than 10000, the data is
written in exponential format according to the format string "%10.3e".
Otherwise the matrix elements are written in fixed format according to
"8.4f".

RETURNS

NO_ERROR on success, or ERROR on a failure.

RELATED

write_matrix_rows, fp_write_matrix_cols

DISCLAIMER

This software is not adequatedly tested. It is recomended that
results are checked independantly where appropriate.